Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detector
- Autores
- Alconada Verzini, María Josefina; Alonso, Francisco; Arduh, Francisco Anuar; Dova, María Teresa; Hoya, Joaquín; Monticelli, Fernando Gabriel; Wahlberg, Hernán Pablo; The ATLAS Collaboration
- Año de publicación
- 2017
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- The electroweak production and subsequent decay of single top quarks in the t-channel is determined by the properties of the Wtb vertex, which can be described by the complex parameters of an effective Lagrangian. An analysis of a triple-differential decay rate in t-channel production is used to simultaneously determine five generalised helicity fractions and phases, as well as the polarisation of the produced top quark. The complex parameters are then constrained. This analysis is based on 20.2 fb−1 of proton-proton collision data at a centre-of-mass energy of 8 TeV collected with the ATLAS detector at the LHC. The fraction of decays containing transversely polarised W bosons is measured to be f1 = 0.30 ± 0.05. The phase between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be δ− = 0.002π+ 0.016π+ 0.017π, giving no indication of CP violation. The fractions of longitudinal or transverse W bosons accompanied by right-handed b-quarks are also constrained. Based on these measurements, limits are placed at 95% CL on the ratio of the complex coupling parameters Re [gR/VL ∈ [−0.12, 0.17] and Im [gR/VL ∈ [−0.07, 0.06]. Constraints are also placed on the ratios |VR/VL| and |gL/VL|. In addition, the polarisation of single top quarks in the t-channel is constrained to be P > 0.72 (95% CL). None of the above measurements make assumptions about the value of any of the other parameters or couplings and all of them are in agreement with the Standard Model.
Facultad de Ciencias Exactas - Materia
-
Ciencias Exactas
Física
electroweak interaction
hadron-hadron scattering
top physics - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- http://creativecommons.org/licenses/by/4.0/
- Repositorio
.jpg)
- Institución
- Universidad Nacional de La Plata
- OAI Identificador
- oai:sedici.unlp.edu.ar:10915/81956
Ver los metadatos del registro completo
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Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detectorAlconada Verzini, María JosefinaAlonso, FranciscoArduh, Francisco AnuarDova, María TeresaHoya, JoaquínMonticelli, Fernando GabrielWahlberg, Hernán PabloThe ATLAS CollaborationCiencias ExactasFísicaelectroweak interactionhadron-hadron scatteringtop physicsThe electroweak production and subsequent decay of single top quarks in the t-channel is determined by the properties of the Wtb vertex, which can be described by the complex parameters of an effective Lagrangian. An analysis of a triple-differential decay rate in t-channel production is used to simultaneously determine five generalised helicity fractions and phases, as well as the polarisation of the produced top quark. The complex parameters are then constrained. This analysis is based on 20.2 fb<sup>−1</sup> of proton-proton collision data at a centre-of-mass energy of 8 TeV collected with the ATLAS detector at the LHC. The fraction of decays containing transversely polarised W bosons is measured to be f1 = 0.30 ± 0.05. The phase between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be δ− = 0.002π<sup>+ 0.016π</sup><sub>+ 0.017π</sub>, giving no indication of CP violation. The fractions of longitudinal or transverse W bosons accompanied by right-handed b-quarks are also constrained. Based on these measurements, limits are placed at 95% CL on the ratio of the complex coupling parameters Re [g<sub>R</sub>/V<sub>L</sub> ∈ [−0.12, 0.17] and Im [g<sub>R</sub>/V<sub>L</sub> ∈ [−0.07, 0.06]. Constraints are also placed on the ratios |V<sub>R</sub>/V<sub>L</sub>| and |g<sub>L</sub>/V<sub>L</sub>|. In addition, the polarisation of single top quarks in the t-channel is constrained to be P > 0.72 (95% CL). None of the above measurements make assumptions about the value of any of the other parameters or couplings and all of them are in agreement with the Standard Model.Facultad de Ciencias Exactas2017-12-04info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/81956enginfo:eu-repo/semantics/altIdentifier/issn/1029-8479info:eu-repo/semantics/altIdentifier/doi/10.1007/JHEP12(2017)017info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International (CC BY 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:15:21Zoai:sedici.unlp.edu.ar:10915/81956Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:15:21.366SEDICI (UNLP) - Universidad Nacional de La Platafalse |
| dc.title.none.fl_str_mv |
Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detector |
| title |
Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detector |
| spellingShingle |
Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detector Alconada Verzini, María Josefina Ciencias Exactas Física electroweak interaction hadron-hadron scattering top physics |
| title_short |
Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detector |
| title_full |
Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detector |
| title_fullStr |
Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detector |
| title_full_unstemmed |
Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detector |
| title_sort |
Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s = 8 TeV with the ATLAS detector |
| dc.creator.none.fl_str_mv |
Alconada Verzini, María Josefina Alonso, Francisco Arduh, Francisco Anuar Dova, María Teresa Hoya, Joaquín Monticelli, Fernando Gabriel Wahlberg, Hernán Pablo The ATLAS Collaboration |
| author |
Alconada Verzini, María Josefina |
| author_facet |
Alconada Verzini, María Josefina Alonso, Francisco Arduh, Francisco Anuar Dova, María Teresa Hoya, Joaquín Monticelli, Fernando Gabriel Wahlberg, Hernán Pablo The ATLAS Collaboration |
| author_role |
author |
| author2 |
Alonso, Francisco Arduh, Francisco Anuar Dova, María Teresa Hoya, Joaquín Monticelli, Fernando Gabriel Wahlberg, Hernán Pablo The ATLAS Collaboration |
| author2_role |
author author author author author author author |
| dc.subject.none.fl_str_mv |
Ciencias Exactas Física electroweak interaction hadron-hadron scattering top physics |
| topic |
Ciencias Exactas Física electroweak interaction hadron-hadron scattering top physics |
| dc.description.none.fl_txt_mv |
The electroweak production and subsequent decay of single top quarks in the t-channel is determined by the properties of the Wtb vertex, which can be described by the complex parameters of an effective Lagrangian. An analysis of a triple-differential decay rate in t-channel production is used to simultaneously determine five generalised helicity fractions and phases, as well as the polarisation of the produced top quark. The complex parameters are then constrained. This analysis is based on 20.2 fb<sup>−1</sup> of proton-proton collision data at a centre-of-mass energy of 8 TeV collected with the ATLAS detector at the LHC. The fraction of decays containing transversely polarised W bosons is measured to be f1 = 0.30 ± 0.05. The phase between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be δ− = 0.002π<sup>+ 0.016π</sup><sub>+ 0.017π</sub>, giving no indication of CP violation. The fractions of longitudinal or transverse W bosons accompanied by right-handed b-quarks are also constrained. Based on these measurements, limits are placed at 95% CL on the ratio of the complex coupling parameters Re [g<sub>R</sub>/V<sub>L</sub> ∈ [−0.12, 0.17] and Im [g<sub>R</sub>/V<sub>L</sub> ∈ [−0.07, 0.06]. Constraints are also placed on the ratios |V<sub>R</sub>/V<sub>L</sub>| and |g<sub>L</sub>/V<sub>L</sub>|. In addition, the polarisation of single top quarks in the t-channel is constrained to be P > 0.72 (95% CL). None of the above measurements make assumptions about the value of any of the other parameters or couplings and all of them are in agreement with the Standard Model. Facultad de Ciencias Exactas |
| description |
The electroweak production and subsequent decay of single top quarks in the t-channel is determined by the properties of the Wtb vertex, which can be described by the complex parameters of an effective Lagrangian. An analysis of a triple-differential decay rate in t-channel production is used to simultaneously determine five generalised helicity fractions and phases, as well as the polarisation of the produced top quark. The complex parameters are then constrained. This analysis is based on 20.2 fb<sup>−1</sup> of proton-proton collision data at a centre-of-mass energy of 8 TeV collected with the ATLAS detector at the LHC. The fraction of decays containing transversely polarised W bosons is measured to be f1 = 0.30 ± 0.05. The phase between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be δ− = 0.002π<sup>+ 0.016π</sup><sub>+ 0.017π</sub>, giving no indication of CP violation. The fractions of longitudinal or transverse W bosons accompanied by right-handed b-quarks are also constrained. Based on these measurements, limits are placed at 95% CL on the ratio of the complex coupling parameters Re [g<sub>R</sub>/V<sub>L</sub> ∈ [−0.12, 0.17] and Im [g<sub>R</sub>/V<sub>L</sub> ∈ [−0.07, 0.06]. Constraints are also placed on the ratios |V<sub>R</sub>/V<sub>L</sub>| and |g<sub>L</sub>/V<sub>L</sub>|. In addition, the polarisation of single top quarks in the t-channel is constrained to be P > 0.72 (95% CL). None of the above measurements make assumptions about the value of any of the other parameters or couplings and all of them are in agreement with the Standard Model. |
| publishDate |
2017 |
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2017-12-04 |
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